 /*******************************************************************************
  * Copyright (c) 2002, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.cheatsheets.registry;

 import java.lang.reflect.Constructor ;
 import org.eclipse.core.runtime.*;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.ui.cheatsheets.AbstractItemExtensionElement;
 import org.eclipse.ui.internal.cheatsheets.*;
 import org.eclipse.ui.model.*;
 import org.osgi.framework.Bundle;

 /**
  * Instances represent registered cheat sheet item extensions.
  */
 public class CheatSheetItemExtensionElement extends WorkbenchAdapter implements IAdaptable {
     private String className;
     private String itemAttribute;
     private IConfigurationElement configurationElement;
     private final Class [] stringArray = { String .class };

     /**
      * Create a new instance of this class
      *
      */
     public CheatSheetItemExtensionElement() {
     }

     /**
      * Returns an object which is an instance of the given class
      * associated with this object. Returns <code>null</code> if
      * no such object can be found.
      */
     public Object getAdapter(Class adapter) {
         if (adapter == IWorkbenchAdapter.class) {
             return this;
         }
         return Platform.getAdapterManager().getAdapter(this, adapter);
     }

     /**
      *
      * @return IConfigurationElement
      */
     public IConfigurationElement getConfigurationElement() {
         return configurationElement;
     }

     /**
      * Answer the classname parameter of this element
      *
      * @return java.lang.String
      */
     public String getClassName() {
         return className;
     }

     /**
      * Answer the itemAttribute parameter of this element
      *
      * @return java.lang.String
      */
     public String getItemAttribute() {
         return itemAttribute;
     }

     /**
      *
      * @param newConfigurationElement IConfigurationElement
      */
     public void setConfigurationElement(IConfigurationElement newConfigurationElement) {
         configurationElement = newConfigurationElement;
     }

     /**
      * Set the className parameter of this element
      *
      * @param value java.lang.String
      */
     public void setClassName(String value) {
         className = value;
     }

     /**
      * Set the itemAttribute parameter of this element
      *
      * @param value java.lang.String
      */
     public void setItemAttribute(String value) {
         itemAttribute = value;
     }

     public AbstractItemExtensionElement createInstance() {
         Class extClass = null;
         AbstractItemExtensionElement extElement = null;
         String pluginId = configurationElement.getContributor().getName();

         try {
             Bundle bundle = Platform.getBundle(pluginId);
             extClass = bundle.loadClass(className);
         } catch (Exception e) {
             String message = NLS.bind(Messages.ERROR_LOADING_CLASS, (new Object [] {className}));
             IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
             CheatSheetPlugin.getPlugin().getLog().log(status);
         }
         try {
             if (extClass != null) {
                 Constructor c = extClass.getConstructor(stringArray);
                 Object [] parameters = { itemAttribute };
                 extElement = (AbstractItemExtensionElement) c.newInstance(parameters);
             }
         } catch (Exception e) {
             String message = NLS.bind(Messages.ERROR_CREATING_CLASS, (new Object [] {className}));
             IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
             CheatSheetPlugin.getPlugin().getLog().log(status);
         }
         
         if (extElement != null){
             return extElement;
         }

         return null;
     }
 }

